Overview

Hepatitis A is a highly contagious liver infection caused by the hepatitis A virus. The virus is one of several types of hepatitis viruses that cause inflammation and affect your liver's ability to function.

You're most likely to get hepatitis A from contaminated food or water or from close contact with a person or object that's infected. Mild cases of hepatitis A don't require treatment. Most people who are infected recover completely with no permanent liver damage.

Practicing good hygiene, including washing hands frequently, is one of the best ways to protect against hepatitis A. Vaccines are available for people most at risk.

Symptoms

Hepatitis A signs and symptoms typically don't appear until you've had the virus for a few weeks. But not everyone with hepatitis A develops them. If you do, hepatitis signs and symptoms can include:

These symptoms may be relatively mild and go away in a few weeks. Sometimes, however, hepatitis A infection results in a severe illness that lasts several months.

When to see a doctor

Make an appointment with your doctor if you have signs or symptoms of hepatitis A.

Getting a hepatitis A vaccine or an injection of immunoglobulin (an antibody) within two weeks of exposure to hepatitis A may protect you from infection. Ask your doctor or your local health department about receiving the hepatitis A vaccine if:

You've traveled out of the country recently, particularly to Mexico or South or Central America, or to areas with poor sanitation

A restaurant where you recently ate reports a hepatitis A outbreak

Someone close to you, such as a roommate or caregiver, is diagnosed with hepatitis A

Causes

Hepatitis A is caused by a virus that infects liver cells and causes inflammation. The inflammation can affect how your liver works and cause other signs and symptoms of hepatitis A.

The virus most commonly spreads when you eat or drink something contaminated with fecal matter, even just tiny amounts. It does not spread through sneezing or coughing.

Here are some of the specific ways the hepatitis A virus can spread:

Eating food handled by someone with the virus who doesn't thoroughly wash his or her hands after using the toilet

Drinking contaminated water

Eating raw shellfish from water polluted with sewage

Being in close contact with a person who's infected — even if that person has no signs or symptoms

Having sex with someone who has the virus

Risk factors

You're at increased risk of hepatitis A if you:

Travel or work in areas of the world where hepatitis A is common

Attend child care or work in a child care center

Live with another person who has hepatitis A

Are a man who has sexual contact with other men

Have any type of sexual contact with someone who has hepatitis A

Are HIV positive

Are experiencing homelessness

Have a clotting-factor disorder, such as hemophilia

Use any type of illegal drugs (not just those that are injected)

Complications

Unlike other types of viral hepatitis, hepatitis A does not cause long-term liver damage, and it doesn't become chronic.

In rare cases, hepatitis A can cause a sudden loss of liver function, especially in older adults or people with chronic liver diseases. Acute liver failure requires a stay in the hospital for monitoring and treatment. Some people with acute liver failure may need a liver transplant.

Prevention

The hepatitis A vaccine can prevent infection with the virus. The vaccine is typically given in two shots. The first one is followed by a booster shot six months later.

The Centers for Disease Control and Prevention recommends a hepatitis A vaccine for the following people:

All children at age 1, or older children who didn't receive the childhood vaccine

Anyone age 1 year or older who is experiencing homelessness

Infants ages 6 to 11 months traveling internationally

Family and caregivers of adoptees from countries where hepatitis A is common

People in direct contact with others who have hepatitis A

Laboratory workers who may come in contact with hepatitis A

Men who have sex with men

People who work or travel in parts of the world where hepatitis A is common

People who use any type of illicit drugs, not just injected ones

People with clotting-factor disorders

People with chronic liver disease, including hepatitis B or hepatitis C

Anyone wishing to obtain protection (immunity)

If you're concerned about your risk of hepatitis A, ask your doctor if you should be vaccinated.

Follow safety precautions when traveling

If you're traveling to parts of the world where hepatitis A outbreaks occur, take these steps to prevent infection:

Peel and wash all fresh fruits and vegetables yourself.

Don't eat raw or undercooked meat and fish.

Drink bottled water and use it when brushing your teeth.

Avoid all beverages of unknown purity, with or without ice.

If bottled water isn't available, boil tap water before drinking it.

Practice good hygiene

Thoroughly wash your hands often, especially after using the toilet or changing a diaper and before preparing food or eating.

Recommended immunizations for children from birth through 6 years old. Centers for Disease Control and Prevention. https://www.cdc.gov/vaccines/schedules/easy-to-read/child.html. Accessed Aug. 8, 2017.

Nelson NP, et al. Update: Recommendations of the advisory committee on immunization practices for use of hepatitis A vaccine for postexposure prophylaxis and for preexposure prophylaxis for international travel. MMWR. 2018;67:43.

Doshani M, et al. Recommendations of the Advisory Committee on Immunization Practices for use of hepatitis A vaccine for persons experiencing homelessness. MMWR Morbidity and Mortality Weekly Report. 2019;68:6.

Hepatitis A questions and answers for the public. Centers for Disease Control and Prevention. https://www.cdc.gov/hepatitis/hav/afaq.htm#E2. Accessed Feb. 22, 2019.

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